A communication system can be seen as a facility that enables communication sessions between two or more entities such as user equipment and/or other nodes associated with the communication system. The communication session may comprise, for example, voice, data, multimedia and so on. A user equipment may, for example, be provided with a two-way telephone call, multi-way conference call or a data communication session. A user equipment may also be provided with a connection to an application server (AS), for example a service provider server, thus enabling use of services provided by the application server.
A communication system typically operates in accordance with a given standard or specification which sets out what the various entities associated with the communication system are permitted to do and how that should be achieved. For example, the standard or specification may define if the user or, more precisely, the user equipment is provided with a circuit switched service and/or a packet switched service. Communication protocols and/or parameters which are used for the connection may also be defined. In other words, a specific set of “rules” on which the communication can be based on needs to be defined to enable communication by means of the system.
Communication systems proving wireless communication for user equipment are known. An example of the wireless systems is a public land mobile network (PLMN). The PLMNs are typically based on cellular technology. In cellular systems, a base transceiver station (BTS) or similar access entity serves wireless user equipment (UE), such as mobile stations (MS) via a wireless interface between these entities. The communication on the wireless interface between the user equipment and the elements of the communication network can be based on an appropriate communication protocol. The operation of the base station apparatus and other apparatus required for the communication can be controlled by one or several control entities. The various control entities may be interconnected.
One or more gateway nodes may also be provided for connecting the mobile network to other networks, for example to a public switched telephone network (PSTN) and/or other communication networks such as an IP (Internet Protocol) and/or other packet switched data networks. For example, if a requested service is provided by a service provider located in other network, the service request is routed via the mobile network to the other network and then to the service provider.
An example of the services that may be offered for subscribers, such as the users, to a communication system is the so called multimedia services. An example of a communication system enabled to offer multimedia services is the Internet Protocol (IP) Multimedia network. IP Multimedia (IM) functionalities can be provided by means of an IP Multimedia Core Network (CN) subsystem, or briefly IP Multimedia subsystem (IMS). The IMS includes various network entities for the provision of the multimedia services.
It is expected that various types of services are to be provided to users by means of different Application Servers (AS) over the IMS systems. Users or subscribers may be able to use services simultaneously from different contact addresses, such as from different user equipment. It is possible for more than one subscriber to use a service simultaneously in a shared or common session. An example of such use may be a game server providing game services for two or more parties to play together.
Users of a shared service might wish to be able to have some control on how the use of the shared service is to be charged. For example, the users may wish to be able to define before using the service if only one of the parties is to be charged for the use of the service even at the stage when it is not known who that party might be. It might also be desirable in certain circumstances to be able to provide a possibility for selecting division of the charges of the service between the users.
It shall be appreciated that these issues are not limited to any particular communication environment, but may occur in any communication system.